A computer contaminated with a worm, virus, or other malicious code can spread the contamination to other computing systems and networks without the knowledge or intent of the computer owner. For example, when a visitor to an enterprise facility brings in a computer that has a contaminated file or system and uses that computer to access an enterprise network, the worms and/or viruses contaminating the computer may be spread to other network elements in the enterprise network. Although virus scans and other security processes may be performed periodically to help restore the computer and to safeguard networks associated with the computer from further damage, such measures are generally remedial in nature. A great deal of damage may be done to the contaminated computer and to networks associated with the computer, however, before the presence of the malicious code is detected and the source of the contamination identified for remedial clean-up.